Researchers with The Samuel Roberts Noble Foundation and Oklahoma State University (OSU) recently tested a new harvesting and extraction system for sweet sorghum. The innovative process could play a future role in ethanol production for regional farmers and ranchers.

The Noble Foundation's Jagadeesh Mosali, Ph.D., and Drs. Dani Bellmer and Ray Huhnke with the Biosystems and Agricultural Engineering Department at OSU tested the juice expression efficiency of a sweet sorghum roller press, which is designed to simulate a new mechanical harvest system developed by an entrepreneur that cuts and presses sweet sorghum in a single action.

The field trial, which took place at the Noble Foundation's Dupy Farm near Gene Autry, Okla., comes at the conclusion of the first year of a three-year study on sweet sorghum. The joint Noble Foundation-OSU study is designed to determine the yield and quality of sweet sorghum's forage under different nitrogen rates as well as improve pressing and fermentation methods for possible ethanol production.

Bellmer and Mosali began the process by developing 21 different treatments, containing three varieties under seven different nitrogen rates.

"It is all about being cost effective," said Mosali, researcher in the Noble Foundation's Agricultural Division. "Farmers and ranchers need to find the hardiest, most efficient variety. Next, they need to be able to use the minimum amount of fertilizer, particularly nitrogen fertilizer, to get the maximum yield. So we're examining all these factors in one study as well as potential harvesting methods."

Sweet sorghum research projects at the Noble Foundation and OSU have been expanded by the creation of the Oklahoma Bioenergy Center (OBC), established in 2007, that advances the biofuels-related research programs of OSU, the Noble Foundation and the University of Oklahoma for the purpose of bringing the biofuels industry to Oklahoma.

Sweet sorghum is similar to grain sorghum, except its stalks are rich in sugars, which can be used as a raw material for fuel-grade ethanol production. Sweet sorghum is a viable ethanol crop for agricultural producers in the varying climates of the southern Great Plains.

To convert sweet sorghum into biofuel, stalks are harvested and juice is extracted by crushing them between rollers. The resulting juice is fermented and distilled for ethanol production. Much like sugarcane, the sugars within sweet sorghum degrade quickly, so the juice must be fermented relatively quickly after harvest.

OSU researchers look to solve the harvesting challenge to offer new opportunities to the budding ethanol industry in Oklahoma.

"There are few inputs, it is a low cost process, and the technology is simple," Bellmer said. "The farmers can produce it right there without requiring a large biorefinery."

The on-site ethanol production could give regionally isolated agricultural producers the ability to establish decentralized plants that are cooperatively owned by a group of farmers and ranchers.

"It's exciting to think that in the near future farmers and ranchers could grow the fuel that would power their farms," Bellmer said. "This would provide rural farmers with an alternative to traditional fuels, as well as infuse the rural economies with additional funds."

While two years remain on the Noble Foundation-OSU study, Bellmer said the initial juice samples extracted during the recent field trial will be taken to her laboratory to be processed and analyzed. This information will be compared to data collected in 2009 and 2010 before recommendation on sweet sorghum variety and fertilizer rates can be reliably made available to the public.

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News Release Issued: October 16, 2008

For media inquiries concerning the Noble Foundation, please contact J. Adam Calaway, Director of Public Relations, at 580.224.6209 or by email at jacalaway@noble.org.

The Samuel Roberts Noble Foundation, Inc. (www.noble.org), headquartered in Ardmore, Okla., is a nonprofit organization conducting agricultural, forage improvement and plant biology research; assisting farmers and ranchers through educational and consultative agricultural programs; and providing grants to nonprofit charitable, educational and health organizations.